Burgess.] 
154 
[February 16 , 
mists, and which, so far as I know, do not occur outside of the 
Lepidoptera. 
Writing somewhat hurriedly for the press, I stated “ I have 
. . . . dissected Vanessa Huntera, a sphingid and a noctuid, 
and found the same conditions as in the Milk-weed Butterfly, so 
it is probable they are characteristic of the Lepidoptera, as one 
would indeed expect from the general uniformity in the anatomy 
of the group.” The words “same conditions” imply rather more 
than I had intended to say, and my friend, Dr. C. S. Minot, after 
studying the anatomy of Aletia, not unnaturally made exception 
to my statement; so I would take this opportunity to ex- 
plain that I had in mind more the general peculiarity of the lepi- 
dopterous aorta, than its exact manifestation in Danais Archippus. 
The following examples will show how far the facts themselves 
actually go, and such modification of the above quoted sentence 
as they may make necessary. 
In Colias Philodice, fig. 1, the aorta is much like that of Danais. 
The posterior, or upward branch is more curved, and the aortal 
chamber a little longer. The anterior branch has a considerably 
larger diameter than the posterior. In Hesperia (sp. ?), fig. 2, this 
Philodice x 11. x 11 
difference between the two branches is very great, the anterior 
being in fact as wide in profile at the aortal chamber, but it is 
much compressed laterally. Its walls are very delicate, while the 
chamber has thick walls, and is as wide as high. The chamber 
